Merge branch 'arnif-master'

Week10/MongoDB.md

@@ -74,12 +74,12 @@ To enable a sharding service in MongoDB you need to set up a shardered cluster s
 Additional reading material about [Sharding] (http://docs.mongodb.org/manual/core/sharding-introduction/)
 
 
-MongoDB does not support traditional sql query language.   Instead it offers its own query language and it is easy 
+MongoDB does not support traditional sql query language.   Instead it offers its own query language and it is easy
 to find good information about that on the official MongoDB website.
 
-MongoDB is a database server that have to be installed to be used.   
+MongoDB is a database server that have to be installed to be used.
 ##Setup
-Ubuntu: 
+Ubuntu:
 > sudo apt-get install mongodb
 
 Mac OSX using brew:
@@ -94,9 +94,9 @@ Mac OSX alternative:
 
 > cp -R -n mongodb-osx-x86_64-2.6.4/ mongodb
 
-The server is started from the command line with the command: 
+The server is started from the command line with the command:
 
-> sudo service mongod start    
+> sudo service mongod start
 This command starts up the mongo daemon.
 
 MongoDB needs a data folder and it has to be created with sudo rights. By default it stores its data in /var/lib and logs in /var/log/mongdb, but you can also create your one like this:
@@ -109,19 +109,19 @@ And then behind closed doors let’s give everyone access rights to this folder:
 
 #Mongo
 
-Mongo is a console based client that can be used to query data in MongoDB.  There are also other tools available online 
+Mongo is a console based client that can be used to query data in MongoDB.  There are also other tools available online
 that have more visual interface as [Robomongo](http://robomongo.org/)
 
 This command lists all databases
-> show database 
+> show database
 
 This command switches or creates the database mydb
 > use mydb
 
 This command shows all collections in mydb.
 > show collections  
 
-To create a collection, create the JSON object 
+To create a collection, create the JSON object
 > var x = {‘user’: ‘hlysig’, ‘course’:’Forritun 1’, ‘grade’:’4’}
 
 To insert into the grades collection give the command:
@@ -136,7 +136,7 @@ Further information can be found on [mongoDB](http://www.mongodb.org)
 > npm install mongoose
 
 ##Getting started
-To include mongoose in your project 
+To include mongoose in your project
 > var mongoose = require('mongoose');
 
 > mongoose.connect('mongodb://localhost/test');
@@ -173,7 +173,7 @@ person.save(function (err, person) {
   if (err) return console.error(err);
   person.info(); //Should say "My name is Dabs"
 ```
-To query for all persons we can do 
+To query for all persons we can do
 ```
 Person.find(function (err, persons) {
   if (err) return console.error(err);
@@ -182,5 +182,86 @@ Person.find(function (err, persons) {
 ```
 For more information about queries see [here](http://mongoosejs.com/docs/queries.html)
 
+# Validating in mongoose
 
+* Validation is defined in the schema
+* Validation occurs when document attempts to be saved, after default values have been saved
+* Validation is asynchronously recursive, when you call the save function validation is executed. If an error occurs your save function callback receives it.
 
+## Simple validation
+
+Simple validation is declared by passing a function to validate and error type to your SchemaType.
+
+Example:
+```
+function validator (v) {
+  return v.length > 10;
+};
+
+new Schema({
+    name: { type: String, validate: [validator, 'my error type'] }
+})
+```
+
+Alternatively you can do the same with this:
+
+```
+var schema = new Schema({
+    name: String
+})
+
+schema.path('name').validate(function (v) {
+  return v.length > 5;
+}, 'my error type');
+```
+
+## Regular expression
+
+You can also validate by using regular expression
+
+Example:
+```
+var schema = new Schema({
+    name: { type: String, validate: /[a-z]/ }
+});
+```
+
+## Asynchronous validation
+
+You can define a validator function with two parameters like:
+```
+schema.path('name').validate(function (v, fn) {
+  // my logic
+}, 'my error type');
+```
+
+Then the function fn will be called with true or false depending on whether the validator passed
+This allows for calling other models and querying data asynchronously from your validator.
+
+
+## Built in validators.
+
+* Strings:
+
+*enum: takes a list of allowed strings.*
+```
+	var Post = new Schema({
+    		type: { type: String, enum: ['smuu', 'foo', 'bar'] }
+	})
+```
+
+* Numbers:
+
+*min: minimum value*
+```
+	var Person = new Schema({
+    		age: { type: Number, min: 10 }
+	})
+```	
+
+*max: maxmimum value*
+```
+	var Person = new Schema({
+    		age: { type: Number, max: 42 }
+	})
+```